VirtualBox-3.2.x-OSE - guest performance issues with guest kernels >=2.6.32

[Polynomial-C]

Hi,

I have set up some Gentoo guest systems running on a Gentoo-host machine (kernel-2.6.32.17 at the time of filing this bug) with eight CPU-cores (2x AMD Opteron 2389, AMD-V is activated). The guests all have four CPUs assigned to them and I don't run more than one of these VMs at the same time.

I observed two problems on the guest machines:

As soon as I am using kernel-2.6.33 or newer in the guest systems they completely freeze after a short period of I/O traffic (like some rsync command or untarring a bigger archive).

When sticking with kernel-2.6.32.x in the guest systems the VM does not freeze but after some bigger compilation sessions (you know, in Gentoo you compile quite a lot ;)) the performance decreases drastically. To give you an example in numbers: Compilation of www-client/seamonkey usually takes about 15 minutes using all four assigned CPU-cores. When this performance decrease occured comilation of the same package takes over two hours still using all four CPUs. htop in the guest shows the CPUs utilized at 100% but htop in the host systems shows that the assigned CPUs only get utilized at roughly 55%-60%.

Please let me know what more information you need. I can attach the kernel .config file from either kernel-2.6.32.x, kernel-2.6.33.x, kernel-2.6.34.x and/or kernel-2.6.35.

[Frank Mehnert]

A good start is a VBox.log file of a session when you observed the performance decrease with 2.6.32 and a VBox.log file when you observed a guest freeze after I/O traffic.

[Polynomial-C]

I have to correct my statement concerning >=kernel-2.6.33 freezes. Not the entire VM is freezing there's just no more I/O happening. For example I can still switch virtual terminals or switch between already opened windows under X but I cannot run anything that needs access to the hard drive.

[Polynomial-C]

I/O freeze with kernel-2.6.34.2

[Polynomial-C]

Performance decrease with kernel-2.6.32.17

[Sander van Leeuwen]

The performance decrease you've observed is fixed in 3.2.10. You'll have to retry the .33 kernel to see if anything has changed there. Please reopen if that's still a valid problem.

[Polynomial-C]

Unfortunately the VM still freezes when there's some bigger I/O operations. This is currently with kernel-2.6.35.7 on both host and guest machines running Gentoo linux.

[Polynomial-C]

Latest freeze with kernel-2.6.35.7

[Frank Mehnert]

Still relevant with VBox 4.1.4?

[Frank Mehnert]

No response, closing.